The present invention relates generally to systems and methods for rendering batteries safe for disposal after use. More specifically, the present invention pertains to battery packs with integrated devices for detecting when the battery is ready for disposal and rendering the battery safe for non-hazardous type disposal. The increased use of batteries in portable and mobile devices, such as cellular telephones and those devices commonly found in hospital environments have created environmental problems owing to the disposal of the spent batteries. For example, many hospitals contract with environmental companies to periodically collect spent batteries from the hospital and dispose of them in an environmentally acceptable fashion. This process is expensive, time-consuming, and not always effective in that a number of batteries end up in standard garbage disposal containers, the contents of which are often incinerated and otherwise disposed by methods that are not always safe. Also, the incineration of such batteries is often hazardous because of the chemical composition of the battery. For example, lithium is a commonly used material in batteries. Lithium reacts quite violently to water, sometimes causing explosions. Such batteries can also emit harmful gases upon partial destruction. What is needed then is a device that renders a battery inert after the usage of the battery is complete. Once in an inert state, the battery may then be treated as standard waste material and incinerated or buried in landfills without concern about environmental safety.
In U.S. Pat. No. 5,717,306 (the “'306 patent”) issued to Shipp, a battery identification and power interrupt system is described. In one embodiment, the '306 patent describes a battery pack that is equipped with a preprogrammed identification device that can communicate with a microprocessor built into the device. Preferably, the battery powers the microprocessor for the purpose of interrogating the battery to ensure that the appropriate battery is used in the device. This is accomplished through a third terminal on the battery that acts as a data terminal to pass information bi-directionally from the battery to the processor and vice-versa. Though not needed to understand the present invention, portions of the '306 patent (incorporated by reference in U.S. Provisional Application No. 60/425,506, of which this application claims the benefit of) are included in the present specification for background information only. In particular, the embodiment of FIGS. 1 to 6 of the present application generally corresponds to the embodiment described and shown in FIGS. 1 to 6 of the '306 patent. The present invention includes an improvement over the '306 patent in that it adds the capability of rendering a battery inert using a third terminal of the battery, for example, a data terminal.